AFAIK the Hellenes were a wonderfully open minded people and their language and their art are a magnificent synthesis of the many culture they visited/raided/traded with on their epic ocean voyages. Not that they weren't also evil tyrannous weak strong brave cruel good bad etc like eveyone else, just making the point that their culture was especially porous and assimilative so they became a carrier for many cultures. The Etruscans and their cultural step-children the Romans adopted it (I'm guessing) because it was so readily adaptable ("yeah that god looks a bit like Zeus, he can be your version of the Thnderer, and his wife is in charge of the household orright?") as well as bweing brilliantly attractive ("you got your statues, your painting, your philosophy, your symposiums...")
Thanks Cyclops,
anyway we might ask this question: why greek culture was so "porous and assimilative", in comparison with other ancient cultures? You talk about religion: I agree, 'cause in my opinion religion was one of the aspects more assimilable.
Then I read in an essay that greek culture made philosophy and science not only to solve practical problems of their real life, but also for pure knowledge. Does it means something for the assimilative process?

There's a substantial caste of Syrian merchants in the Roman empire IIRC. I'm always reading about Syrian merchant colonies in Aquae Sulis in Brittania and at Marseille. Now were these "Syrians" Antiochian hellenes, Tyrian/Sidonian poeni, or something else? Assyrian descendants?
Mmm... It's a curious question. I remember that a lot of Etruscan pottery was recently found tombs near Siracusa, one of the greatest cities of Magna Graecia, so in that city we might suppose there were Etruscan merchants.